Cardiac index is a tool often used by healthcare providers such as perfusionists. Cardiac index is a cardiodynamic measure based on cardiac output, which is the amount of blood pumped by the heart per unit time, measured in liters per minute (1/min). The cardiac output can also be thought of as the amount of blood the heart pumps through the circulatory system in a minute. To provide the cardiac index, cardiac output is indexed to a patient's body size by dividing the cardiac output by the body surface area (BSA) of the patent. Thus, the cardiac index is typically provided as (1/min)/m2. There are several algorithms to calculate a patient's body surface area, such as DuBois, Boyd and infant algorithms, for example. Typically, these algorithms are provided in large tables in reference books that can be utilized by the appropriate health care provider. Target cardiac flow rates are typically calculated by perfusionists using a combination of a body surface area equation and desired cardiac index values.